[Python] String index out of range error when updating adding 1 to my list index [closed]

In my Python program, I'm trying to make a lists index tick up every time a condition is met, so I can edit what is displayed when it is run multiple times. I am getting the error "IndexError: string index out of range" and I don't know why, especially since I'm doing the same thing somewhere else multiple times and it works fine.

My code:

questions = ["Placeholder question 1 (c)", "Placeholder question 2 (b)", "Placeholder
question 3 (a)", "Placeholder question 4 (d)", "Placeholder question 5 (d)"]

answers_solutions = ["c", "b", "a", "d", "d"]

number_to_text = ["one", "two", "three", "four", "five"]

score = 0
questions_left = 5
question = questions[0]
answers_solution = answers_solutions[0]
question_number = number_to_text[0]

answer = input(f"""________
Score: {score}
Questions left: {questions_left}
______________
Question: {question_number}:
{question}
a, b, c, or d?
""")
if answer == answers_solution:
print("Correct!")
score + 1
question_number [+ 1]
answers_solution [+ 1]
question [+ 1]
questions_left - 1
else:
print("Incorrect ")
question_number [+ 1]
answers_solution [+ 1]
question [+ 1]
questions_left - 1

what I want to happen:

when I print answer = input:

(f"""________
Score: {score}
Questions left: {questions_left}
______________
Question: {question_number}:
{question}
a, b, c, or d?
""")


All the variables in curly brakets have changed to the next thing In their list.

What actually happens:

if answer == answers_solution:
print("Correct!")
score + 1
question_number [+ 1]
answers_solution [+ 1] -(if the answer is correct) IndexError: string index out of range
question [+ 1]
questions_left - 1
else:
print("Incorrect ")
question_number [+ 1]
answers_solution [+ 1] -(if the answer is incorrect)IndexError: string index out of range
question [+ 1]
questions_left - 1


this only happens happens for the variable "answers_solution".

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